Upper respiratory tract
NORMAL FLORA
Mouth:
Staph epidermidis
*Actinomyces
Mycoplasma
*Candida
Viridians streptococci
Bacteroides spp.
Peptostreptococcus
*Fusobacterium
*Spirochaetes
Nose/Throat:
*Staph aureus
Staph epidermidis
*Streptococcus pneumoniae
*Streptococcus pyogenes
*Moraxella catarrhalis
*Haemophilis influenzae
*Neisseria meningitidis
Bacteroides
Corynebacterium
Viridans streptococci
Peptostreptococcus
Fusobacterium
COMMON PATHOGENS &
DISEASES CAUSED
Mouth:
Actinomyces
Fusobacterium
Spirochaetes
Candida albicans (fungi)
Nose/throat:
Staph aureus
Streptococcus pneumoniae
 Otitis media (1)
 Sinusitis (1)
 LRTIs
 Meningitis
 Pneumonia
Streptococcus pyogenes
 Pharyngitis
 Acute glomerulonephritis
 Rheumatic fever
Haemophilus influenzae
 Otitis media (2)
 Sinusitis (2)
 Epiglottitis
 LRTIs
 Meningitis
Bordetella pertussis
SPECIMENS
ANTIBIOTICS COMMONLY USED
Throat swab
 tonsillar areas, posterior
pharynx and any areas of
inflammation
 Tongue must be depressed in
order to minimize
contamination with oral
secretions
 most throat infections are
viral in origin,  throat swabs
are only useful if there is a
suspicion of a serious overlying
bacterial infection
Nasopharyngeal swab
 useful for isolation of
Bordetella pretussis
Blood
Nasal swab
 determines the carrier state
for S. aureus
Acute bacterial rhinosinusitis (Streptococcus
pneumoniae or Haemophilus influenzae and
less frequently by Moraxella catarrhalis) –
use amoxicillin
If allergic to penicillin:
Cefuroxime or cefaclor or doxycycline
Acute pharyngitis and/or tonsillitis:
Streptococcus pyogenes
phenoxymethylpenicillin
 Whooping cough
Moraxella catarrhalis
 Otitis media (3)
 Sinusitis in children (2)
Neisseria meningitidis
Viruses:
 Adenovirus
 Rhinovirus
 Enterovirus
 Influenzae, parainfluenzae
 RSV
Lower respiratory tract
NORMAL FLORA
None
COMMON PATHOGENS &
DISEASES CAUSED
Common:
Streptococcus pneumoniae
Haemophilis Influenzae
Moraxella catarrhalis
Mycoplasma
Mycobacterium
Less common:
Staph aureus
Pseudomonas aeruginosa
SPECIMENS
Sputum
 expectorated from the
LRT,
 often contaminated with
saliva, mouth and URT
organisms.
Blood
Bronchoalveolar lavage
ANTIBIOTICS COMMONLY USED
Non-specific cough: lignocaine via nebuliser
Acute exacerbations of bronchiectasis:
Amoxyicillin
If sputum grows P. aeruginosa: ciprofloxacin
Aspiration pneumonia: benzlpenicillin PLUS
metronidazole
Standard short term TB: isoniazid plus
Legionella
Candida albicans (opportunistic
fungi)
Class
QUINOLONES
Drug
Ciprofloxacin (C-flox®, Profloxin®)
250, 500, 750 mg (14)
rifampicin plus ethambutol plus pyrazinamide
Influenza: oseltamivir
Indications
mostly G-ve cover
Side effects
rash/itch
complicated UTI
n&v
diarrhoea
abdo pain/dyspepsia
Traveller’s diarrhoea
b'cidal; inhibit
bacterial DNA
synthesis
Shigelosis
Norfloxacin (Roxin®, Noroxin®)
400 mg (14)
tendonitis, myalgia
dizzy
Prostatitis
photosensitivity
Salmonella, Typhoid
crystalluria
CNS (dizziness, headache, ↓ seizure threshold)
**Cipro interacts with warfarin (↑INR) and
phenytoin (↓conc.)
Cat B3 (fetal arthropathy)
avoid in b/f
Penicillins
Moderate - Broad Spectrum:
G+ve, some G-ve
Amoxycillin (Amoxil, Moxacin)
250, 500, 1000mg
25mg/mL, 50mg/mL,
100mg/mL
b'cidal; interfere
with bacterial cell
Amoxycillin + Clavulanic acid
URTI (G+ve)
Pneumonia
UTI (G-ve)
Bites, clenched fist injuries
Otitis media, sinusitis
H. pylori eradication
WT
diarrhoea
nausea
rash
urticaria
**ALLERGY** occurs in 10% of ppl – crossreactivity between penicillins, cephalosporins, and
carbapenems
wall peptidoglycan
synthesis
(Augmentin, Clavulin)
500/125, 875/125
25mg/mL, 6.25mg/mL
80mg/mL, 11.4mg/mL
Narrow spectrum:
G+ve
Staph
Dicloxacillin (Diclocil, Dicloxsig)
250, 500mg
Staph. skin infections
Pneumonia
Osteomyelitis
Septicaemia
cholestatic hepatitis (augmentin, di/fluclox,
cilicaine VK)
Flucloxacillin (Flopen, Staphylex)
250, 500mg
25mg/mL, 50mg/mL
Strep
IV penicillins (benzylpenicillin, benzathine penicillin,
phenoxymethylpenicillin, procaine penicillin)
C/I: allergy to penicillin,
cephalosporin or carbapenems
dose reduce in RI
Safe to use in pregnancy and breastfeeding
Phenoxymethylpenicillin (Abbocillin VK, Cilicaine VK)
250, 500 mg
Macrolides
b'static; inhibit
bacterial protein
synthesis by binding
to 50S ribosomal
sub-unit
1. Roxithromycin (Rulide, Biaxsig)
150, 300mg
50mg dispersible
tonsillitis/pharyngitis
skin infections
Class indications:
Alternatives to penicillins and
cephalosporins in allergic
patients.
MAC and pertusis treatment and
prophylaxis
______________________
2. Erythromycin (Eryc, E-mycin)
250, 400mg
Chlamydial infections
(azithromycin > clarithromycin)
n/v
diarrhoea
abdominal pain
candidal infection
rash (Stevens-Johnson syndrome)
40mg/mL, 80mg/mL
EES
H. pylori eradication
(clarithromycin)
Respiratory tract infections (all
except azithromycin)
CAP (roxithromycin, azithromycin)
3. Clarithromycin (Klacid, Clarac)
250, 500mg
Recurrent tonsillitis
(roxithromycin)
Skin infections (roxithromycin)
QT elongation
E>C>A (not with R)
Erythromycin causes infantile hypertrophic pyloric
stenosis in infants <2 weeks old
Drug interactions
and abdo
discomfort
E>C>R>A
Trimethoprim
b'static;
competitively
inhibits bacterial
folate production
essential for
bacterial growth(G ve)
4. Azithromycin (Zithromax)
500, 600mg
C/I: allergies to macrolides
Alprim, Triprim
300 mg
Uncomplicated lower UTI
Epidymo-orchitis
Prostatitis
Safe to use in pregnancy and breastfeeding
Trimethprim
fever
itch
rash
n/v, gastric upset
hyperkalaemia*
blood dyscrasias
megablastic anaemia
Co-trimoxazole
trimethoprim + sulfamethoxazole
Bactrim, Resprim, Septrim
80mg/400mg
160mg/800mg
DS, Forte
8mg/mL, 40mg/mL
susp.
Shigellosis (GI infection)
Traveller’s diarrhoea
Stevens-Johnsons syndrome
C/I: allergy to trimethoprim,
severe renal impairment*,
megablastic anaemia due to
folate deficiency, pregnancy (1st
trimester)
Sulfamethoxazole
photosensitivity
headache, drowsiness
allergy to sulfamethoxazole,
hepatic impairment, late
pregnancy
Tetracyclines
Doxycycline (Doxylin, Doxy, Vibramycin)
50, 100 mg
Acne
Malaria prophylaxis
anorexia
sore mouth
ADEC Cat B3; avoid in first trimester
Safe in b/f
GI upset (n/v, dairrhoea, epigastric burning)
teeth discolouration
enamel dysplasia
Respiratory tract infections
b’static; inhibit
bacterial protein
synthesis by
reversibly binding to
30S sub-unit of the
ribosome
CAP
Exacerbation of chronic bronchitis
Acute bacterial sinusitis
photosensitivity
Chronic prostatitis
↑ intracranial BP  causes headache
(doxycycline)
oesophageal ulcers
inhibition of bone growth
Minocycline; abdominal cramps and vestibular
toxicity (dizziness, vertigo, ataxia)
C/I: allergy to
tetracycline,
children <8 due to
teeth discolouration
and enamel
dysplasia
D/I: retinoids, MTX,
rifampicin
Minocycline (Akamin, Minomycin)
50, 100 mg
Acne
OR (with Orfloxixin and
Rifampicin) leprosy
ADEC Cat D
Avoid in b/f (short courses of 7-10 days ok)
Nitromidazoles
Metronidazole (Flagyl, Metrogyl)
200, 400 mg
40mg/mL
Anaerobic bacterial infections (G+ve
and G-ve)
Protozoal infections
n/v
abdominal pain
diarrhoea
anorexia
Dental infection
metallic taste, furry tongue
Aspiration pneumonia
CNS effects (dizziness, headaches)
Bacterial vaginosis
Paraesthesia, peripheral neuropathy
H. pylori eradication
Wounds (e.g. diabetic foot ulcer)
disulfuram reaction when taken with alcohol
Tinidazole (Fasigyn, Simplotan)
500 mg
Rifampicin
Rifadin, Rimycin
150, 300, 600mg
C/I: treatment with disulfiram,
renal/hepatic impairment
TB
MRSA
ADEC Cat B2
Safe to use in b/f
GI irritation (n/v, cramps, diarrhoea)
orange-red discolouration of body fluids
staining of soft contact lenses
rash
increase liver enzymes
arthralgia, myalgia
CNS (dizziness, headache, ataxia, confusion)
hepatotoxicity
rifamycins are
b’cidal; inhibit
bacterial RNA
polymerase
Reserve rifamycins
for MRSA,
mycobacterial
infections and
prophylaxis of
mengitis and
epiglottitis
Fuscidic acid
Nitrofurantoin
C/I: allergy to rifampicin
D/I: rifampicin induces CYP450
enzymes  lots of significant
drug interactions
Fucidin®
250 mg
Macrodantin®
50, 100 mg
MRSA with rifampicin
Acute lower UTIs
Prophylaxis or long term
suppressive treatment in
recurrent UTI
inhibits bacterial
protein, DNA, RNA
and cell wall
synthesis
Avoid use in elderly and renally
impaired as more likely to
experience peripheral
neuropathy.
Cephalosporins
same mechanism of
Moderate Spectrum
G+ve: anti-strep, staph
G-ve: E. coli, Klebsiella
Cephalexin
Staphylococcal and
streptococcal infections in
ADEC Cat C, use with caution
Safe to use in b/f
lethargy
GI upset
drowsiness
vertigo
headache
n/v
anorexia
peripheral neuropathy
hepatotoxicity
pulmonary toxicity
rash
GI disturbance (n, d, electrolyte disturbance)
rash
action as penicillins
 cross-sensitivity
Cephalexin (Keflex)
250, 500 mg (20)
people with mild-to-moderate
penicillin allergy
UTIs due to susceptible Gramnegative bacteria
25, 50 mg/mL
headache
rarely anaphylactic shock, bronchial obstruction
Epididymo-orchitis
Surgical prophylaxis
(cephazolin)
5-10% cross-reactivity with allergy to penicillins
______________________
+ anti-himophilus activity (against Hib)
Cefaclor (Ceclor)
375 mg CR (10)
25, 50 mg/mL
Otitis media (particularly in
children)
Respiratory tract infections
caused by H. influenzae
Acute bacterial sinusitis
Cefuroxime (Zinnat)
(cefuroxime - gonococcal
infections)
______________________
Ceftriaxone (Rocephin)
→ Broad Spectrum
Aminoglycoside
Gentamicin
Pneumonia
Bacterial meningitis
Septicaemia
Sexually acquired epididymoorchitis (with doxycycline)
Empirical treatment of serious
Gram-negative infections
C/I: immediate/severe allergy to penicillins
Ototoxicity (hearing loss, tinnitus, balance
problems, n/v)
Hepatotoxicity
Neuromuscular toxicity (potentially fatal e.g.
respiratory depression – treat with calcium
gluconate)